Many chips or die with integrated circuits are contained in electronic devices. Within the integrated circuit industry, there is a continuing effort to increase integrated circuit device density and speed. As integrated circuits become smaller, the number of interconnections and the amount of heat generated per square inch may increase accordingly. Increased heating of an integrated circuit device may affect the performance of the device and may cause permanent damage. Semiconductor packages may be designed to address some of these issues.
An important function carried out by the substrate is that of dissipating heat generated by the die during operation. A multilayer substrate is desirable because it allows increased circuit design flexibility; however, this can also increase the path required for thermal conduction, which decreases the heat dissipating ability of the package. In general, the substrate provides a thermal conduction path away from the die by way of the substrate die pad through vias connecting the substrate die pad to the heat spreader, and through the heat spreader to, for example, a printed circuit board.
However, due to the arrangement of conventional substrates as well as the fabrication process associated with conventional substrates, the thermal conduction path through the semiconductor package is severely limited. By way of example, thermal conduction is particularly limited in multi-layer substrates. Due to inefficient thermal conduction, heat dissipation is severely limited and, therefore, semiconductor devices using such packages can suffer from poor performance and poor package reliability.
For example, a flip chip package may accommodate interconnection requirements of high-density integrated circuits. In a typical flip chip package, an integrated circuit may be mounted to the top surface of a package substrate that serves as an interconnection device. The package substrate typically consists of top and bottom surface buildup layers of interconnect circuitry disposed on a substrate core. As current is passed through the top and bottom buildup layers, heat may be generated, which may cause the package substrate to self-heat. The substrate core is typically made of an organic material that is not thermally conductive, and so acts as a thermal insulator to the buildup layers.
A current solution to remove heat from a flip chip package is to attach a heat spreader in thermal contact with a backside surface of the integrated circuit. The heat spreader is typically attached to a solder resist area around the perimeter of the top buildup layers. Because the solder resist area is not thermally conductive, there may be no path for heat transfer from a self-heated package substrate to the heat spreader. Therefore, the heat spreader may do little to remove heat from the self-heated package substrate. The heat spreader also adds undesirable size to the dimensions of the package as well as the space requirements within the system and product. Multiple integrated circuits or packages only exacerbate the issues with heat transfer and constraints of size.
Across virtually all applications, there continues to be growing demand for reducing size and increasing performance of integrated circuits. The seemingly endless restrictions and requirements are no more visible than with products in our daily lives. Smaller and denser integrated circuits are required in many portable electronic products, such as cell phones, portable computers, voice recorders, etc. as well as in many larger electronic systems, such as cars, planes, industrial control systems, etc. As the demand grows for smaller electronic products with more features, manufacturers are seeking ways to include more features, reduce the size, and improve the thermal performance of the integrated circuit packages.
Thus, a need still remains for an integrated circuit package system to provide improved thermal performance, function, area, volume, and manufacturing yield. In view of the increasing demand for improved integrated circuits and particularly more functions in smaller products at lower costs, it is increasingly critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.